The use of computer networking techniques is rapidly growing. Computer networks are being used to interconnect a wide variety of devices from industrial control systems to home appliances. In these emerging networks, many `embedded` computers are being attached to networks. As used herein, the term `embedded` computer refers to a device having a processor within it and in some cases limited user I/O ("input and/or output"), but lacking a complex user interface such as a large display and full keyboard. The term `node` refers to a device that is connected to the network and is capable of communicating with other network devices. Similarly, the term `embedded node` refers to a device having an embedded computer within it that is connected to a network and is capable of communicating with other network devices or nodes. The term `local` or `local coupling` refers to being coupled directly to other network nodes by a communication bus without any intervening devices. Conversely, the term `remote` or `remote coupling` refers to being coupled to other nodes indirectly, i.e. through another device, such as by "tunneling" through another network or device, or by modem.
Although embedded computers have conducted communications over networks in the past, network management systems supporting them have had various limitations. The term `network management` as used herein refers to management of configurations, connections, and other parameters related to the particular network. In most instances where network management functionality is required, larger computers (e.g., user workstation) have been used to provide such functionality. This is problematic in networking environments where such larger computers are impractical or unfeasible. For example, in a small to medium sized HVAC (i.e., heating, ventilation and air-conditioning) system, it is not economically prudent to include a larger computer on the network with the embedded controller. Thus, for any network management function to be performed, it is conventional for a technician to arrive with a portable computer and attach it to the network, thereby facilitating certain network management functions.
As one networking example, ECHELON networks (developed by Echelon Corporation of Palo Alto, Calif.) are used in a variety of embedded processor applications and are especially well-suited to networking process and environmental control devices. As used herein, the term `ECHELON network` refers to a network consisting of devices or nodes that implement a LONTALK protocol. LONTALK is a trademark of the aforementioned ECHELON Corporation and refers to a protocol used by applications to communicate with nodes in an ECHELON network. An overview of the LONTALK protocol is described in section 8 of Motorola LonWorks Technology Device Data, Rev. 3.1 (hereinafter, "LonWorks Tech. Publication") published in 1997 by Motorola Corporation of Palatine, Ill. The LONTALK protocol provides a means of exchanging data between devices using Network Variables as described in sections 7.2 and 7.3 of the LonWorks Tech. Publication. There are various data structures within an Echelon device, which must be correctly configured for the device to function correctly. These data structures are described in Appendix A of the LonWorks Tech. Publication. The messages defined in the LONTALK protocol which are needed to configure these various data structures and otherwise control and monitor the device are described in Appendix B. Sections 7, 8 and Appendices A and B of the LonWorks Tech. Publication are fully incorporated by reference herein. One example of a prior art network management device for an ECHELON network is the model NSS-10 from Echelon Corp. shown in FIG. 1. The NSS-10 includes a hosted ECHELON node (i.e., an ECHELON communication chipset having a processor available for executing user applications) that includes a network database and a single client application locally attached thereto. Only a single, local, client application is supported. Another example of a prior art network management system for an ECHELON network is the model LNS system from Echelon Corp. shown in FIG. 2. LNS is a non-embedded solution and is too expensive and impractical for many ECHELON networks. For example, being non-embedded, LNS would have to be coupled remotely to the ECHELON network to support the network architectures common in the HVAC industry, i.e. by "tunneling" through other networks or by serial port modem. Such remote coupling generally introduces signal timing and other complexities into the system.
Thus, there does not exist a network management system for an ECHELON network that is embeddable, inexpensive and supportive of multiple clients. The present invention is a solution to this problem.